Geneva, Illinois: Riverbank Laboratories 1918. First Edition. 20 pages 8 3/4 x 11 1/4 inches. (22.3 cm x 28.5 cm). Publisher's stiff tan wrappers with black printed front cover duplicating title page. Provided in the originally issued Riverbank Laboratories button and string flapped manila envelope with limitation number on outside. Individually numbered limitation of 200 copies (so stated on copyright page). Binding post ghosting from folder on the cover. Fine. Wraps. 
Not normally included in the so-called 'Riverbank Publications' which included numbers 15-22, this is one example of other work published by Riverbank in related fields.
Shulman, An Annotated Bibliography of Cryptography, 1976, p82 (which attributes authorship to H. O. Nolan).